It is possible to get more than 12 x 1/35 Soldiers, up to the item limit of 99, as you can receive them as a prize in the Speed Square in the Golden Saucer. The same goes for the Masamune Blade and Super Sweeper items, neither of which have a purpose in the game.

I have the psx platinum version of the game and i found a use for these items in all my play throughouts of the game.

the 1/35 Soldiers and super sweeper are part of a set o items to protect fort condor.
If you have a set number of cash and soldiers / super sweeper they appear and protect the reactor. The specifics i don't have but are related with the mini quest of each major development in the story will activate a new battle in fort condor. (ex: before getting the buggy/ after getting the buggy).

I know this isn't much but i saw the super sweeper protecting the reactor when in mini battle mode in fort condor. (i don't have a picture,sorry )
I did not use cheats and i couldn't find the trigger for this either then taking the car to do ALL battles in fort condor until i reached nibelheim.